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d=rootcommit.com; s=hostingermail-a; t=1761518932; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uFsO6MOvX/5QN9XiCW8717+gVZ3oyi7YrYXpJc6qfWo=; b=jenUQCRo/Am12+0noROadVkvTh0uDbTiGgY5PW4GBhmXmSaweUQKOWiqC8gaa4JoV2Hrxp 4VbTgPWu61Tk1DvjY+2IpygBCE2UP01UTkG3AQulIqUUjqE4LBrC/G8aJB+wqPJ8AEsoKs qGOq/3qi62DOGVdrZcDFlfXTW/nB4EbiEDJtpaSCjUoXfItt8ZXxSX4lSjagPgdn7O0wzv SC/oDFSwVohEEX9imI6yRPg38l24DubnNoKg6C40g7Qtl3bmVYmssFTEcv3Ir9/eEETvBT evLH3aD9wSdZqyUKp7ZQSM8eywYe/8y5lnMgeHDy+mBvdvPVyuCUu0wGpA0krg== Message-ID: <4bdad288-250b-4e94-abea-eb231fba5beb@rootcommit.com> Precedence: bulk X-Mailing-List: sophgo@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: michael.opdenacker@rootcommit.com, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, unicorn_wang@outlook.com, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, alex@ghiti.fr, alexander.sverdlin@gmail.com, rabenda.cn@gmail.com, thomas.bonnefille@bootlin.com, chao.wei@sophgo.com, liujingqi@lanxincomputing.com, devicetree@vger.kernel.org, sophgo@lists.linux.dev, linux-riscv@lists.infradead.org Subject: Re: [PATCH 2/3] arm64: dts: sophgo: add initial Milk-V Duo S board support To: Joshua Milas , Inochi Amaoto References: <20251011014811.28521-1-josh.milas@gmail.com> <20251011014811.28521-3-josh.milas@gmail.com> Content-Language: en-US, fr From: Michael Opdenacker Organization: Root Commit In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Date: Sun, 26 Oct 2025 22:48:50 +0000 (UTC) X-CM-Envelope: MS4xfCvqkUVMbgTTDbHBA0d4cZBu8FEN3OWccx7Z3P1XKUivUx4Y68YFJpjG2DHVo3P5lB3Ny+/8w0V3ajRhGWzoYRUuaCkXdvFvHcWTnCnbhFz/PrdrWC+x COM5aFHJVvKFr/TS8TzixCnKhPhzdj9F1cfiwoyCXMPAS7pXgasqCyvGi//OA5t4SeP7b2FDSbjXfXy1AVcC2dv6FZnC70B6jl2TXyls2IVUEAz66hPQhnNX W5HaqF3f6vdnVH0zTYj7Rw3WokajdiUoQcaes/olNhpXTR3Ld6XT88k0RRYbZ3G+sbO+g/wQYIHbUV26cukqWAaAZJ39l7/NFaKC+Ax/8H35WFixldDWhNmH Gkxj9HAOcLxINWk6EQIwQk7YXHH/3GAhirc1dTXOrRLXY21Qibf0mRZb2+xOOR9gplI1hoPpropN94wkvlE2eyNylLcA8xtjPptBAHoWDzyiJE/R0FzA7lcW u94QFzgavtxqJW144Djci+uYdLHMp4kObiBWY1v9sSgFQezyQkdQJB5sJ6XMjBXyxMbP3REFSeOhjR9qszHNlvfU2Un6AhM7ePi1Q79UQ27lMP/3wvv4Yd/n +P+f/QkuVcGpT0T23r7ISE8NKEBSuxST3WHxTuVy1SqP0zX8RelYByh9/a5grzuJ1rZ8zqcgZslAWZ0Cl/l+wZ55doQVqWtDLOr/ThG1mzAxHgbyl+YMCQcP s3N2FHaIdEcL7qj8T370YNQQSlY4jap/8379yoznKiZS5VKvbBmL/IbdD5hdSucMQlHxQGn07kmNMkSCXOxJbn2AtwVwu+O/cIutf3kP58xOMdpzcPrv1Yzt VTI0v9w8oSv+E+QDDiQmQpLzs+SV2IO9maYa13KvUW4p1EyLKcvsWRhzMnPXMJlnSXezO3/QWaBpF/HHB/f3IMuH8ewAQ2PWBoxQSlffglVzhZLZcO0tz6Ki mZTfsQ== X-CM-Analysis: v=2.4 cv=GbNFnhXL c=1 sm=1 tr=0 ts=68fea554 a=zy7iCUYNTH43UiyTonfErQ==:617 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=YzZgpwwcAAAA:8 a=d70CFdQeAAAA:8 a=SDwY5gupPOl0iZWIF84A:9 a=QEXdDO2ut3YA:10 a=diELbSsDbaqdzccPbx55:22 a=NcxpMcIZDGm-g932nG_k:22 X-AuthUser: michael.opdenacker@rootcommit.com Hi Joshua Thanks a lot for working on support for Milk-V Duo S. I'll be happy to test your V3 :) On 10/26/25 22:35, Joshua Milas wrote: > Inochi, > > Thanks for pointing me twards duo-pinmux. I was able to use it to get > the default config which is uart0, spi3, and i2c4. I can change the > dts to match, but... > >> I suggest enabling devices that are accessed by default > Would we rather enable anything that can be accessed by the pinmux? If I understand correctly, you can't do that because there will be conflicts. From the Duo S pinout diagram (https://milkv.io/duo-s/duos-pinout.webp), on headers 41 and 39, you have to choose between MIPI, I2C2, PWM12/13 or SD1. If at least 2 of these are selected at the same time, there will be a conflict, and I assume that the pinctrl controller driver will flag it. Then it sounds complicated to define a default combination for the whole board, because it's like a default use model. Who gets to choose? What Inochi suggests is to follow the vendor kernel choice, which would correspond to the way the vendor intended the board to be used. However the community could choose another default way to use the board, so the choice may be up to the first contributor to the mainline kernel for this board, possibly revised through later discussions. I guess there are cases when the choice is easy: - When only one configuration is available for a set of pins - When there are important devices on I2C or SPI buses on the board. Then, you want to find a way to prioritize such buses. Fortunately, I guess the board design also guides you to the right choice. I was facing the the same question today on another board, and that's why I'm happy it's raised here. As thousands of DTS files have been written before, I'd love to hear from people with experience on this topic. Are guidelines written anywhere for board DTS creators? Cheers Michael. -- Michael Opdenacker Root Commit Yocto Project and OpenEmbedded Training course - Learn by doing: https://rootcommit.com/training/yocto/